python - 我的 tkinter 窗口立即关闭

Question

我正在尝试制作一个程序来判断某个人的年龄是否为吸烟年龄。我能够使其在命令行中工作，但我决定制作一个实际的窗口程序。 http://pastebin.com/0HettMLx是我当前的代码。

import random
import sys
import os
import time
import tkinter
from tkinter import messagebox, Label, Button, StringVar


age=StringVar

window = tkinter. Tk()#creates a new window
window.title("Are you old enough to smoke?")#title
window.geometry("300x200")#window size
window.wm_iconbitmap('favicon.ico')#icon

photo=tkinter.PhotoImage(file="images.png")#picture in said window
w=tkinter.Label(window, image=photo)
w.pack()

lbl=tkinter.Label(window, text="Please enter your age.", bg="light salmon", fg="blue2")#label text & color
lbl.pack()

ent=tkinter.Entry(window, text="(Your age here)", textvariable=age)
ent.pack()

def callback():
   button_pressed=True
   while True:
       if (age) >= 18:
            print('You are legally able to smoke.')
       else:
            print("You are not of legal age to smoke.")

       if (age)>= 18:
            print ("You are legally able to smoke cigarettes.")
       if (age)>=21:
            print("You are legally able to smoke marijuana.")
       if (age)>=40:
            print("You're above the age of forty,\nDo you really need to ask if you're old enough?")
       if (age)<=12:
            print("You're to young to smoke get out of here.")

btn=tkinter.Button(window, text="Confirm", bg="sienna1", fg="blue2", relief="groove", command=callback())
btn.pack()

window.configure(background='light salmon')#back ground

window.mainloop()# draws window

但是每次我去运行它时，窗口都会打开但立即关闭。它只显示按钮、标签和条目，效果很好，但一旦我开始尝试在按钮中实现 command=callback ，它就不起作用了。我只是想知道如何解决它关闭问题。

运行python34，win7-64位。

Answer 1

当您为按钮分配回调时，您需要分配可调用的。 command=callback() 正在将 callback() 返回的内容 (None) 分配给命令，而不是设置 command=callback:

btn=tkinter.Button(window, text="Confirm", bg="sienna1", fg="blue2", relief="groove", command=callback)

你的程序可能会崩溃，因为你试图通过像普通变量一样简单地引用它来访问age，StringVars有点不同。要获取 StringVar 的值，您需要对其调用 get() 。您还需要使用 StringVar() 而不仅仅是 StringVar 正确初始化 StringVar。您还需要在调用 Tk()之后执行此操作:

window = tkinter.Tk()  # creates a new window
age = StringVar()  # you need to call this after the line above

最后，在回调中，您需要正确访问 StringVar 的值并将其转换为整数，这最容易在回调顶部完成，方法是定义一个新变量来保存整数，然后替换 年龄。此回调中也不需要有 while True: 循环，特别是因为您永远不会打破它:

def callback():
    ageint = int(age.get())
    button_pressed=True

    #  Remove while True: loop and fix indentation below

    if (ageint) >= 18:     # Replace all "age" with "ageint" from here on
        print('You are legally able to smoke.')
    ....